The conventional paper shredder is generally provided at the paper entry thereof with a microswitch or LED electric eye for sensing the entry of paper to be shredded so as to trigger the operation of the motor. As the motor is started, the paper shredding tool of the paper shredder is driven by the motor to execute the paper-shredding operation.
Such a conventional paper shredder as described above is defective in design in that the paper shredding action is brought to a halt before the rear end of the paper is shredded. In order to overcome such a deficiency as described above, the conventional paper shredder is provided with a time delay circuit in conjunction with the microswitch or electric eye to enable the shredding tool to continue operating for additional 2-3 seconds after the rear end of the paper has passed the microswitch or electric eye. However, the addition of the delay circuit to the paper shredder results in an increase in cost of making the paper shredder. Moreover, the electronic components are often susceptible to the environmental factors, such as temperature and humidity, which undermine the longevity and the reliability of the delay circuit.